1. Field of the Invention
Units and apparatuses consistent with what is disclosed herein relate to a customer replacement unit monitor (CRUM) unit mountable in a consumable unit of an image forming apparatus, and an image forming apparatus using the same, and more specifically, to a CRUM unit which is able to use an existing universal memory controller while requiring a reduced number of connecting terminals to connect to an image forming apparatus, and an image forming apparatus using the same.
2. Description of the Related Art
Various types of electronic products are developed with the help of the advancing electronic technology. As the computers are widely distributed, the distribution rate of computer-related peripherals is enhanced. These peripherals are provided to enhance utilization of the computers. A representative example includes an image forming apparatus such as a printer, a scanner, a copy machine, or a multifunction unit.
The image forming apparatuses use an ink or a toner to print images on paper sheet. The ink or the toner is used (i.e., consumed) whenever an image forming job is performed, and depleted when used for a certain period time. In this case, a unit storing the ink or the toner should be newly replaced. An accessory or a unit that can be replaced during use of the image forming apparatuses is referred to as a consumable unit or a removable unit. The term ‘consumable unit’ will be used herein for convenience of explanation.
The consumable units include not only the units that need to be replaced due to depleting ink or toner, but also the units that need to be replaced for reduced possibility of provisioning good printing quality due to deteriorating features after a certain period of use. Specifically, not only the respective color developers, but also the component such as an intermediate transfer belt may correspond to a consumable unit, as the belt is depleted or “consumed” during use. This consumable unit needs to be replaced at proper replacement intervals.
The replacement intervals may be determined by using a use status index of the image forming apparatus. The use status index indicates the degree the image forming apparatus has been used, and may include, for example, a number of paper sheets printed and outputted in the image forming apparatus or a number of dots forming images. The image forming apparatus may determine the time for replacing each consumable unit by counting the number of paper sheets or dots.
Recently, each consumable unit is mounted with a customer replacement unit monitor (CRUM) unit for a user to correctly determine the time to replace the consumable unit.
When a consumable unit is mounted in the image forming apparatus, CRUM unit may communicate with the image forming apparatus through the consumable unit. The consumable unit includes a power terminal to receive the power provided from the image forming apparatus. Therefore, the power provided from the image forming apparatus is delivered to the power terminal, and CRUM unit may receive the power from the power terminal and operate accordingly.
However, in view of structure, the power terminal to provide the power may be one of factors to increase a number of terminals for the consumable unit or a number of interfaces for the CRUM unit. Further, increase in a number of terminals or interfaces may increase a size of the consumable unit or CRUM unit, which affects the cost of the consumable unit or CRUM unit.
Therefore, recently suggested is a method of connecting the image forming apparatus with CRUM unit only with three terminals (clock terminal, data terminal, and ground terminal) in which the power terminal is removed.
However, because the above mentioned method modifies the related method of generating clocks according to the standard I2C communication, there is a problem that the CRUM unit cannot be implemented using existing universal IC.
Therefore, a new method is necessary, which is capable of implementing CRUM unit by using an existing universal IC while reducing a number of connecting terminals between the image forming apparatus and CRUM unit.